Hi Michel,

I had a look at your example (poutre_offset.gh) with the shell that is connected to an eccentric beam. 

The results look a bit surprising but are correct. The reason is, that beam and shell act together like in a Vierendeel beam. There is no sufficiently stiff shear connection between shell and beam.

I attached an example to illustrate the fact:

VierendeelBeam.gh

In order to achieve an efficient shear connection one would have to add diagonals between shell and beam - like for a truss. An alternative would be to model the beam as a shell also. 

Best

Clemens

Hi Clemens,

I had a look to your model. I understand. Could you give more details on the formulation of the eccentricity feature? It should be fine if we had choice for a section with eccentricity between full or partial connection.

I have several questions :

- no material is defined. Which is the default material?

- I suppose that there is also a default crossection ?

-O-Profile section : null thickness should mean filled profile

-I made a test (attached) with two flat section (with weak inertia, inertia given by eccentricity) and calculate the deflection. I don't find the same deflection. Hand calc gives 0.001356m. Karamba gives 0.04409m. It means that it takes a partial connection (as you said in your answer : no sufficiently stiff shear connection). But which one ?

Best regards,

Michel

VierendeelBeam_B.gh

Hi Michel,

eccentricities are rigid: it's a kinematic relation between the endpoints and the centroid of a beam. Therefore eccentricities have no material and no cross section. 

O-Profile section: null thickness means filled profile is a good idea. I will add that in the next version - thank's.

Your box-profiles have zero height so there would be no space for the flanges. The current version of Karamba unfortunately doesn't issue a warning in case of impossible cross section shapes and instead calculates something. Either select a larger height or use the cross section values Karamba comes up with: Use a generate Cross Section Table component, plug a panel to its output, stream it to a .csv-file and open it with e.g. Open Office to have a look at them.

Best,

Clemens

to Mohammad Azinkia,

hey buddy, could you pass your definition file here?

however, i think the problem will solve by a greater relation through the beams' kind and the load (how would you might use the components for defining beams?), or, as i should say firstly, it will be more understandable if you attach the file, otherwise my suggest is a bullet in the dark!

Thank you Mahdi for attention.

here is the file.

1.gh

Hi Mohammad,

there are two things you have to change in your definition:
- flatten the element input at the assemble-component. Otherwise you get three different models instead of one
- Feed a list of cross sections into the cross section optimization component. 

Best,
Clemens

Thank you Clemens!! Best help as always.

It works well.

another question: we should analyze structure in x and y by force to analyze what is structure reaction and cross section.Is it any way to have maximum cross sections between x and y direction?If yes how?

In huge project, if we want to construct our structure how can we have output of the cross sections optimized?here I just see a cloud of fonts.

You get the optimized cross section for each element by disassembling the model and then disassembling the elements. In case this does not work as intended with Karamba 1.0.2. send me an e-mail (info@karamba3d.com).

Regarding your previous post: the cross section optimizer computes the cross sections in such a way that their utilization is less than 100% for all load cases. If you have e.g. wind blowing from two directions create two load-cases (see manual).

Best,

Clemens

How can we use double cross section in karamba for e.g. we want use double "IPE" for column or beams.

At the moment there is no direct way to define double IPE cross sections.

You could set up a cross section table with the exact cross section properties of double IPEs, but set their type to e.g. Box-cross section. When displayed you would see box cross sections which have the physical properties of double IPEs.

Best,

Clemens

Thanks Clemens!

Tony: thank you for uploading the video.

Best,

Clemens

Hi Clemens,

I don't understand Princ Stress results. I made a simple wall loaded in its plane, downwards loads on each mesh. I expected to have princ Stress nearly horizontal at bottom and top of wall. Instead I get something that seems to depend on triangle orientation : see attached. gh file attached also.

Thanks for your help.

Michel

wall01-princStress.JPG

wall01-Supports_Loads.JPG

shell_test.gh

Hello. I am new to using karamba so I am fairly unfamiliar with how the components work. I am interested in using karamba to evaluate stresses for various surface forms, and then using the results to place more, or larger, structural members where there are the highest stresses. Is there a good example file for how to do this? Or can anyone point me in the right direction? Thanks.  

Hi Adam,

welcome to Karamba,

you can figure out what all you need by checking out the examples below:
http://www.karamba3d.com/category/examples/

by any kind of analysis, if you check the model rendering to figure out the Utilization or Displacement, you can handle the structure you've designed, and absolutely the definition you've written is important also,
so just write down a path-controled defining for your elements (as there are few examples with this solution in the link above) to find out the point you looking for.
Good Luck Buddy!

Hi, I have a problem when I try to install karamba on my pc.

I have Rhino 4, my pc is 64bit  resolution and I have grasshopper (december updated). When I've installed it, the plugin doesn't appear on the grasshopper screen. Why?

Which version should be ok for me? I tried a lot of version of karamba but they did'nt work. Well, before the updating (with the previous version of karamba) it worked.

thank you

GS

Dear Michel Cassagnes (four posts below),

the shell structure you analyze in shell_test.gh is essentially a simply supported beam. If the loads would be placed only at the upper nodes of the structure the first principal stresses on the bottom would be aligned with the boundary there and the second principal stress would be zero and at right angle to the boundary.

The fact that there are loads on all points of the structure makes the first  principal stress in the center of the bottom triangles deviate from the horizontal direction.  

Best,

Clemens

Dear Clemens,

Thanks for your answer. I modified the file to have loads at the upper nodes. Result on princ stress directions is the same. What do I make wrong ?shell_test.gh

Best regards,

Michel

Dear Michel,

thank you for your example. The first principal stress direction of the bottom elements should be horizontal - that is for sure. I haven't found an explanation yet, why Karamba does not display them correctly. If one selects the boundary conditions of a cantilever (shell_test_cp.gh) the directions come out as expected. As soon as there are horizontal or vertical supports on the other end the directions turn. I have to look into that.

Three things regarding your definition: You support the shell at two points only. This leads to theoretical stress singularities there and the solution does not converge with decreasing mesh size.

The second thing is, that the shell elements in Karamba have no in-plane rotational stiffness. In case of flat shell patches it is sometimes necessary to lock the rotation of one node about an axis perpendicular to the patch.

Your shell is very thin (1cm) relative to its span. That is the reason why it does not compute for some mesh settings.

Best,

Clemens

Hey,

New problem in reinstalling Karamba happened, what this runtime error is about? and how can we fix this up!?

thanks in advance!

hi I wanna ask how to apply a surface in "shape optimization irregular structure 5" example which ı draw manually

In order to install Karamba 1.0.3. with the latest release of Grasshopper 0.9.0052 or higher you need to change the Karamba installation path to the folder where Grasshopper resides. This can be e.g. ‘C:\Users\admin\AppData\Roaming\McNeel\Rhinoceros\5.0\Plug-ins\Grasshopper {B45A29B1-4343-4035-989E-044E8580D9CF}\0.9.56.0′ for Grasshopper 0.9.0056.

Best,

Clemens

Hey All,

immediately with no introduction,

i wana calculate optimized support position on a supposed waffle ceiling, adapted to Persian Girih's Geometry,

the definition attached here got involved the beams rounded the base module but i cana define the lines of the girih,

here we have 2 question:

1- how can i make a range out of my item list to be checked by galapagos for selecting the best position of supports?

2- what's wrong with my modeling method (as i know there is something i haven't noticed), that it could not define as beams for the base of girih's module?

P.S: the definition has been written by Paneling Tools in some parts

thanks

surface%20subdivision.gh

Hi all!

I am new to this magic world of Grasshopper and its plugin, so here it is my question:

How can i assign a Curve element such an arc to the "line to beam" panel? It only takes the end points of the curve and makes a straight line..

Or what's the right way to have a curved "finite element" to work on!?

Cheers

n order to install Karamba 1.0.3. with the latest release of Grasshopper 0.9.0052 or higher you need to change the Karamba installation path to the folder where Grasshopper resides. This can be e.g. ‘C:\Users\admin\AppData\Roaming\McNeel\Rhinoceros\5.0\Plug-ins\Grasshopper {B45A29B1-4343-4035-989E-044E8580D9CF}\0.9.56.0′ for Grasshopper 0.9.0056.

for me only worked ...Plug-ins\Grasshopper\Libraries

in case anyone is struggling with the install like me

Hello,

Having an install issue with 0.9.0061, with Karamba version 1.0.4.  It seemed to install just fine, but upon opening GH, the components do not load.  No errors are thrown, it's just not there.  Perhaps I'm missing something simple?

Cheers,

n

Hello Nick,

did you install Karamba in the right directory? It should be the same as that where 'Grasshopper.dll' resides. You can find out the location of Grasshopper by selecting 'Tools' in the Rhino menu then 'Options...', 'Plug-ins' on the left, 'Grasshopper' on the right and the button 'Properties'. 

Another source of the problem could be that the bitnesses of Karamba and Rhino do not match.

Best,

Clemens

Hi Clemens,

I gave your suggestions a shot.  I plugged in the location for GH as noted in the Plug-in properties, but without success.  The GH .dll is in (x86)Grasshopper for Rhino 5, so I tried to re-install there, ans had the same results. 

As a note, I selected the 32 bit Karamba version, since my Rhino 5 is installed as such. 

Thanks again for your assistance.  I'll keep trying ...

n

Hi Clemens,

I’ve been testing Karamba for a while now, trying to optimize a simple form based on its load transfer. Using a cylinder as a basic form, I try to put a horizontal force on it consisting of five circles. I want these circles to scale in a manner (in Galapagos) so I can get an optimized force flow as a result. In this case the cylinder would become wider at the bottom and narrow at the top. Instead of receiving this form I always get a straight cylinder with the smallest radius for all circles. Do you know where I’m going wrong with my settings? In the attached example I minimized the mass and displacement. Is that correct resp. what other settings do I have to make? I’d be very thankful for some input about this.

Marco

diff_radius_scales.gh

Hi Marco,

on first inspection I think there are two possible reasons for the behavior of your structure:

• The value of the horizontal load is constant but the area of the mesh-load increases with increasing size of the structure. Thus a smaller structure means less load.
• You minimize mass and maximum deflection. These have different physical units. Therefore you need to apply a weighting factor to one of them in order to combine them into one meaningful objective value. 

Best,

Clemens

Hi Clemens,

Thanks a lot for the input. I didn’t really know how to apply a weighting factor to mass and deflection so I only changed the loads in order to have the same amount and intensity in any case. This works fine when I only optimize the max. displacement although I’m not sure if the result is 100% correct. Could you please take a look at the attachment one more time and maybe give me another hint of how to apply the weighting factor? Thanks in advance.

Marco

diff_radius_scales_02.gh

Hi Marco,

the necessity of weighting factors is the main shortcoming of single objective optimization algorithms in case you have more than one design target. There is no right or wrong - setting this factor is a matter of trial and error.

You could use e.g. Octopus which can do multi-objective optimization without the need of pre-set weighting factors.

Best,

Clemens

Hi Clemens,

Thanks a lot for your reply. It's good to know that Octopus might be a better tool for multiple optimization. Once again - thank you for your help.

Best,

Marco

http://www.grasshopper3d.com/photo/album/show?id=2985220%3AAlbum%3A...

some impressions of my master thesis which is based on karamba.
karamba was a great help.

Hi there! i had a problem installing karamba. I managed to install it eventually by installing it at "C:\Users\me\AppData\Roaming\Grasshopper\Libraries". I can see karamba now in grasshoper ,but i still canot use the assemble component. I instaalled karamba to other computers and it seems that when instaling it in the folder Program Files (x86)\Grasshopper for Rhino 5\ it seems to work completeley fine. The problem is whenever i instal grasshopper it never installs it on the "grasshopper for rhino 5" folder, so that folder does not exist. when i see the computers of some friends that location is the instalation folder for grasshopper. The thing is when i instal grasshopper there is no option to choose where it will be installed, so I dont know how to fix this. I have seen that others that had similar problems and tried to follow the instractions that where proposed, but nothing works still. Any ideas?

Hi Sofoklis, with the new versions of grasshopper (>0.9.0060 or so) and Karamba 1.0.4 you have to look up the installation folder of GH in Rhino (Tools/Options.../Plug-ins/Grasshopper - Properties). This is where Karamba 1.0.4 needs to be installed (and to where the installation path needs to be changed).

Sorry for the inconvenience. The issue will be solved in the next release of Karamba.

Best,

Clemens 

Hi

im a bit comfused. (And not with my sexuality)

How can I create solid rectangular cross sections which are normal for wood and concrete structures?

Hi,

use the 'Trapezoid-Profile'-component and set upper and lower width to equal values.

I have installed karamba1.04 for grasshopper 0.90064,why it doesn't show in grasshopper?

Did you change the Karamba installation target directory to where grasshopper.dll resides? Did you install Karamba-64-bit for Rhino5-64bit and Karamba-32-bit for all other versions of Rhino? Did you have a look at http://www.grasshopper3d.com/group/karamba/forum/topics/karamba-use... and http://www.grasshopper3d.com/group/karamba/forum/topics/help-reques...?

Best,

Clemens

Hi,

you mean I should install two karamba 32bit and 64bit, if I have both version of rhino in my computer?

Now I have rhion 4 and rhino 5 32bit & 64bit both. I installed karamba 1.04 for rhino 64bit free version in my grasshopper for rhino 5 folder, it does show in the grasshopper folder, but when I open rhino and grasshopper, it doesn't show on the tool bar and I didn't find the Draw All Components in Grasshoppers View-menu mentioned in the Karamba installation booklet.

I am trying to analyze the structural behaviors of a brick masonry vault and a masonry shell structure. In karamba there is no material property of brick masonry in the material list. How can I solve this problem?

Hi, maybe you find this helpful: http://www.grasshopper3d.com/group/karamba/forum/topics/masonry-str....

Best,

Clemens

The result of karamba analysis is too big compare with my grasshopper model even after I reduce the radius, can I change the unit of karamba to make it proper? I tried to look for the "karamba.ini" mentioned in the booklet, but didn't find it.

Thanks!